PROCESS ECONOMICS PROGRAM

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1 PROCESS ECONOMICS PROGRAM SRI INTERNATIONAL Abstract Mod0 Park, California Process Economics Program Report No. 176 STYRENE AND p-methylstyrene AND POLYMERS (November 1984) The ethylbenzene dehydrogenation process remains dominant for making styrene; some styrene is coproduced in the manufacture of propylene oxide. The process for making styrene from toluene via stilbene and that for making styrene from toluene and methanol are not yet economic. Costs for these processes are presented. We have evaluated processes for three types of polystyrene: general purpose polystyrene (GPS), impact-modified polystyrene (IPS), and expandable polystyrene (EPS). GPS is now universally made by the continuous bulk process; IPS is mostly and preferably made by the continuous bulk process, although batch suspension and batch bulksuspension processes are still used; EPS is made by the batch suspension process. Copolymers of styrene with maleic anhydride, methyl methacrylate, and acrylic acid, respectively, are also evaluated. The copolymer with acrylic acid has a low molecular weight. We also evaluated the manufacture of p-methylstyrene from toluene and ethylene. Costwise p-methylstyrene is barely competitive with styrene. Its polymers have some performance advantages over those of styrene, but these are not sufficient to justify substantial replacement. With surplus production capacity for styrene already in place, the growth of p-methylstyrene is expected to be slow. PEP'84 YCY

2 Report No. 176 STYRENE AND p-methylstyrene AND POLYMERS by YEN-CHEN YEN with contrtbutlons by JONG-TAIN HUANG a t cl I m A private report by the November 1984 PROCESS ECONOMICS PROGRAM Menlo Park, California 94025

3 . For detailed marketing data and information, the reader is referred to one of the SRI programs specializing in marketing research. The CHEMICAL ECONOMICS HANDBOOK Program covers most major chemicals and chemical products produced in the United States and the WORLD PETROCHEMICALS Program covers major hydrocarbons and their derivatives on a worldwide basis. In addition, the SRI DIRECTORY OF CHEMICAL PRODUCERS services provide detailed lists of chemical producers by company, product, and plant for the United States and Western Europe. ii

4 CONTENTS 1 INTRODUCTION... 2 SUMMARY Commercial Aspects... Economic Aspects... Styrene and Polymers... p-methylstyrene and Polymers... Technical Aspects... Styrene from Benzene and Ethylene via Ethylbenzene... Styrene from Toluene and Ethylene via Stilbene... Styrene from Toluene and Methanol... p-methylstyrene from Toluene and Ethylene... General Purpose Polystyrene... Impact Modified Polystyrene... Expandable Polystyrene... Poly(Styrene Maleic Anhydride)... Poly(Styrene-Methyl Methacrylate)... Poly(Styrene-Acrylic Acid)... 3 INDUSTRY STATUS STYRENE PROM BENZENE VIA ETHYLBENZENE... Chemistry... Review of Processes... Evaluation of an Integrated Plant Producing Styrene from Benzene via Ethylbenzene... Process Description... Process Discussion... Cost Estimates.... Ethylbenzene Production... 5 OTHER PROCESSES FOR PRODUCING STYRENE... Styrene from Pyrolysis Naphtha... Styrene from Ethylbenzene by Oxidative Dehydrogenation... Styrene from Toluene and Ethylene via Stilbene... Styrene from Toluene and Methanol... Styrene from Benzene and Ethylene Oxide... Styrene from 4-Vinylcyclohexene... Styrene Coproduced with Propylene Oxide from Ethylbenzene via Hydroperoxide... Conclusions iii

5 CONTENTS 6 p-methylstyrene Chemistry... Review of Processes... io Process Description... Process Discussion... ii: Cost Estimates POLYSTYRENE Chemistry Review of Processes Bulk (Mass) Process Suspension Process (and Bulk-Suspension Process) Emulsion Process Solution Process General Purpose Polystyrene by a Bulk Process Process Description Process Discussion Cost Estimates Impact Modified Polystyrene by a Bulk Process Process Description Process Discussion Cost Estimates Expandable Polystyrene by a Batch Suspension Process Process Description Process Discussion Cost Estimates IPS by Batch Suspension Process COPOLYMERSOFSTYRENE Chemistry Review of Processes Styrene-Maleic Copolymers....' 158 Styrene Copolymers with Methacrylate or Acrylic Acid Other Copolymers A Batch Solution Process for Manufacturing a Rubber-Modified Copolymer of Styrene and Maleic Anhydride Process Description Process Discussion Cost Estimates iv

6 CONTENTS a COPOLYMERS OF STYRENE (continued) A Continuous Bulk Process for Manufacturing a Rubber- Modified Copolymer of Styrene and Methyl Methacrylate Process Description Process Discussion Cost Estimates A Continuous Bulk Process for Manufacturing a Low Molecular Weight Copolymer of Styrene, alpha-methylstyrene, and AcrylicAcid Process Description Process Discussion Cost Estimates General Comments on Costs for Making Copolymers POLYMERS OF p-methylstyrene Chemistry ; Review of Processes Properties of p-methylstyrene Polymers Specific Gravity Cross-Linking Heat Distortion Temperature and Vicat Softening Temperature Transparency, Color Mechanical Strength MeltFlow Susceptibility to Other Additives Prospects for p-methylstyrene p-methylstyrene at 55c/lb p-methylstyrene at 38c/lb p-methylstyrene at 32c/lb APPENDIX A PROPERTIES OF COMMERCIAL STYRENE POLYMERS APPENDIX B SOME USEFUL INFORMATION FOR DESIGN OF PS REACTIONS PATERTSUMMARYTABLES CITED REFERENCES PATENTREFERENCES V

7 ILLUSTRATIONS 3.1 Interrelationships between Ethylbenzene, Styrene, and Polystyrene Styrene from Benzene and Ethylene by Alkylation and Dehydrogenation FlowSheet A Dehydrogenation Reactor Styrene from Benzene via Ethylbenzene Effect of Operating Level and Plant Capacity on Production Cost Styrene by Methanol Alkylation of Toluene Flowsheet p-methylstyrene from Toluene FlowSheet p-methylstyrene from Toluene Effect of Operating Level and Plant Capacity on Production Cost General Purpose Polystyrene by a Continuous Bulk Polymerization Flowsheet General Purpose Polystyrene by a Continuous Bulk Polymerization Single Line Plant Effect of Operating Level and Plant Capacity on Product Value Impact Modified Polystyrene by a Continuous Bulk Polymerieation (Reaction Section) Flowsheet Impact Modified Polystyrene by a Continuous Bulk Polymerization Single Line Plant Effect of Operating Level and Plant Capacity on Product Value Expandable Polystyrene by a Batch Suspension Polymerization Flowsheet a.1 Poly(Styrene-Maleic Anhydride) By a Batch Solution Process Flowsheet Vii

8 ILLUSTRATIONS a.2 Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Flowsheet A Low Molecular Weight Copolymer of Styrene, eiethylstyrene and Acrylic Acid By a Continuous Bulk Process Flowsheet p-methylstyrene Product Value as a Function of Plant Capacity B.l Viscosity of PS (M = 60,000) and Recommended Ranges of Agitators B.2 Relative Heat Transfer Coefficient as a Function of Percent Polystyrene Solids Based on Viscosity Relationship Shown in Figure B.l B.3 Vapor Pressure of p-methylstyrene and p-ethyltoluene Viii

9 TABLES 2.1 Cost Features of Styrene Production Cost Features of Polystyrene Production Cost Features of Styrene Copolymer Production Cost Features of p-methylstyrene Production World Ethylbenzene and Styrene Producers in Styrene Production in Styrene Markets World Polystyrene Producers in Major Producers of Styrene and Polystyrene and their World Capacities Polystyrene Production in Polystyrene Markets World Styrene Copolymer Producers in Ethylbenzene from Benzene and Ethylene by Alkylation Patent Sunnnary Styrene from Ethylbenzene by Dehydrogenation Patent Sunnnary Styrene from Benzene via Ethylbenzene Design Bases and Assumptions Styrene from Benzene via Ethylbenzene Stream Flows Styrene from Benzene via Ethylbenzene Major Equipment Styrene from Benzene via Ethylbenzene Utilities Summary Styrene from Benzene via Ethylbenzene Total Capital Investment Styrene from Benzene via Ethylbenzene Production Costs Comparison of Different Design Bases Ethylbenzene by Vapor Phase Alkylation Production Costs IX

10 TABLES 5.1 Oxidative Dehydrogenation for Making Styrene from Ethylbenzene Patent Summary Styrene from Toluene and Ethylene via Stilbene Production Costs Styrene by Methanol Alkylation of Toluene Total Capital Investment Styrene by Methanol Alkylation of Toluene Production Costs Catalyst for Alkylation of Toluene or Ethylbenzene Patent Summary Methylstyrene from Ethyltoluene by Dehydrogenation Patent Summary p-methylstyrene from Toluene Design Bases and Assumptions p-methylstyrene from Toluene Stream Flows p-methylstyrene from Toluene MajorEquipment p-methylstyrene from Toluene Utilities Summary p-methylstyrene from Toluene Total Capital Investment p-methylstyrene from Toluene Production Costs p-methylstyrene from Toluene 35 Million lb/yr Capacity Production Costs Reactors for Polystyrene Bulk Process Bulk (Mass) Polymerization for Making General Purpose Polystyrene Patent Summary Bulk (Mass) Polymerization for Making Impact Modified Polystyrene Patent Summary X

11 TABLES Some Commercial Continuous Bulk Processes for Making Polystyrene Effect of Bulk Process Production Conditions on Properties of Polystyrene Suspension Polymerization for Making General Purpose or Impact Modified Polystyrene Patentsummary Bulk-Suspension Process for Polymerization of Styrene Patent Summary Expandable Polystyrene Patent Summary Compositions of Polystyrene Patent Summary Devolatilization of Polystyrene Patentsummary Miscellaneous Processes for Styrene Polymerization Patent Summary....., General Purpose Polystyrene by Bulk Polymerization Design Bases and Assumptions General Purpose Polystyrene by Continuous Bulk Polymerization Stream Flows General Purpose Polystyrene by Continuous Bulk Polymerization Major Equipment General Purpose Polystyrene by Continuous Bulk Polymerization Utilities Summary General Purpose Polystyrene by Continuous Bulk Polymerization Total Capital Investment General Purpose Polystyrene by Continuous Bulk Polymerization Production Costs General Purpose Polystyrene by Bulk Polymerization Costs for Multiline Plants xi

12 TABLES 7.19 Impact Modified Polystyrene by Bulk Polymerization Design Bases and Assumptions Impact Modified Polystyrene by Continuous Bulk Polymerization Major Equipment Impact Modified Polystyrene by Continuous Bulk Polymerization Total Capital Investment Impact Modified Polystyrene by Continuous Bulk Polymerization Production Costs Impact Modified Polystyrene by Bulk Polymerization Costs for Multiline Plants Polystyrene by Bulk Polymerization Comparison of Cost Estimates Expandable Polystyrene by Suspension Polymerization Design Bases and Assumptions Expandable Polystyrene by Batch Suspension Polymerization Stream Flows Expandable Polystyrene by Batch Suspension Polymerization Major Equipment Expandable Polystyrene by Batch Suspension Polymerization Utilities Summary Expandable Polystyrene by Batch Suspension Polymerization Total Capital Investment Expandable Polystyrene by Batch Suspension Polymerization Production Costs Impact Modified Polystyrene Comparison of Costs for Bulk and Suspension Processes a.1 Styrene Maleic Anhydride Copolymers Patent Summary Xii

13 TABLES a.2 a a a.9 a a Copolymers of Styrene and Acrylic Acid, Acrylate, and Methacrylate Patent Summary... Copolymers of Styrene and alpha-methylstyrene and Other Styrene Homologues Patent Summary... Styrene Copolymers Similar to ABS Patent Summary... Miscellaneous Copolymers of Styrene Patentsummary... Polystyrene Chemically Modified Patentsummary... Poly(Styrene-Maleic Anhydride) by a Batch Solution Brocess Design Bases and Assumptions Poly(Styrene-Maleic Anhydride) by a Batch Solution Process StreamFlows... Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Major Equipment Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Utilities Summary Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Total Capital Investment Poly(Styrene-Maleic Anhydride) by a Batch Solution Process Production Costs Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Design Bases and Assumptions Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process StreamFlows Xiii

14 TABLES a a a Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Major Equipment Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Utilities Summary Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Total Capital Investment Rubber-Modified Copolymer of Styrene and Methyl Methacrylate by a Continuous Bulk Process Production Costs Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid Design Bases and Assumptions Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Stream Flows Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process MajorEquipment Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Utilities Summary Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Total Capital Investment Low Mol Wt Copolymer of Styrene, alpha-methylstyrene, and Acrylic Acid by a Continuous Bulk Process Production Costs Poly(p-Methylstyrene) Patent Summary xiv

15 TABLES 9.2 Copolymers Containing p-methylstyrene or p/m-methylstyrene Patent Summary Blends and Applications of Poly(p-Methylstyrene) Patent Summary Use of p-methylstyrene Instead of Styrene Estimation of Market Penetration of p-methylstyrene in the United States xv